Rotary pump



P 5, 1967 I K. E GLAss' 3,339,490

ROTARY PUMP Filed April 4, 1966 3,339,490 ROTARY PUMP Kenneth E. Glass, Fort Thomas, Ky., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed Apr. 4, 1966, Ser. No. 539,786 3 Claims. (Cl. 103-103) This invention pertains to rotary pumps in general and particularly to a casing for a rotary pump which will reduce the losses due to boundary layer separation of the incoming fluid as it diffuses into the pumping chamber.

In many types of rotary pumps, and particularly in nonclog type rotary pumps it is desirable to cause the incoming fluid to diffuse immediately upon entering the pumping chamber. This diifusion can be obtained by providing a conical inlet to the pumping chamber. However, since a fluid boundary layer is formed due to the fluid passing through the conical inlet, losses are incurred in the pump efliciency because of the separation of this boundary layer as the fluid diffuses into the pumping chamber. With applicants invention a moving layer of fluid is provided about the pump inlet. The incoming fluid sees this moving layer of fluid as it enters the pumping chamber and diffuses with the moving layer of fluid so that no boundary layer separation occurs.

It is therefore the general object of this invention to provide a rotary pump wherein boundary layer losses due to fluid diffusion in the pumping chamber are minimized.

An additional object of the subject invention is to provide a rotary pump wherein a moving layer of fluid is provided about the pump inlet tangentially located relative to the incoming fluid.

These and other objects of the subject invention will become more fully apparent as the following description is read in light of the attached drawing showing one modification of a rotary pump consrtucted in accordance with the invention.

Referring to the drawing, the invention is shown in connection with a rotary pump having a cylindrical outer wall 6 and a rear wall 7. The rear wall of the pump may be connected to the outer cylindrical wall in any conventional manner such as by screws 8. The outer wall 6 is provided with a tangentially positioned discharge opening 9.

An impeller having a plurality of circumferentially spaced radially extending blades 11 is mounted on a drive shaft 12 extending through the rear wall 7 of the pump. The front of the pump is closed by a wall 13 having a central opening 14 therethrough. This central opening or inlet 14 is axially aligned with the center line of the impeller. The front wall 13 is provided with an annular recess 16 completely surrounding the pump inlet 14. This recess extends from the inner peripheral surface of the outer wall 6 of the pump and terminates tangentially to the pump inlet.

As fluid enters the pump, it moves into the eye of the impeller and is forced outward creating a primary vortex in the region 17 about the tip of the impeller blades 11 and the interior peripheral surface of the outer wall 6.

- United States Patent This primary vortex and the impeller blading induce a secondary vortex in the pumping chamber 18. A portion of the fluid in the pumping chamber passes out the discharge of the pump. With applicants invention an additional vortex is trapped in the recessed area 19 of the front wall of the pump and this assumes the form of a rotating annulus or ring about the pump inlet. The fluid in this trapped vortex follows the contour of the recess 16 and presents a moving boundary of fluid tangent to the fluid entering the pumping chamber through the pump inlet. This incoming fluid is then quickly diffused into the pumping chamber with the forced vortex and losses due to boundary layer breakdown are not incurred.

Although only one embodiment of the subject invention is herein shown and described, it will be obvious to those skilled in the art that modifications can be effected without departing from the spirit of the invention and it is intended that all such modifications as come within a reasonable interpretation of the appended claims be covered.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A rotary pump comprising front and rear walls connected together by a circumferential end wall to define a pumping chamber, said end wall having a single continuously smooth inner surface, a pump impeller supported for rotation within said pumping chamber, an inlet opening through said front wall permitting access of fluid to be pumped into said pumping chamber, a discharge opening in said end wall permitting fluid to exhaust from said pumping chamber, and a pocket formed by a continuation of the single continuously smooth inner surface of said end wall defining an annular chamber in said front wall tangent to and located about said inlet opening, said annular chamber being open to said pumping chamber whereby a portion of the fluid therein enters said annular chamber and is redirected into said pumping chamber tangentially to the fluid entering said inlet opening.

2. The rotary pum-p set forth in claim 1 wherein said pump impeller is laterally spaced from said front wall a distance substantially equal to the size of said discharge opening.

3. The rotary pump set forth in claim 1 wherein said annular chamber is semicircular in cross section.

References Cited UNITED STATES PATENTS 2,635,548 5/ 1953 Brawley 103-103 3,167,021 1/1965 Sence 1 03-1 15 3,171,357 3/1965- Egger 103-115 3,190,226 6/1965 Judd 103-115 FOREIGN PATENTS 444,333 5/ 1927 Germany.

21,286 1901 Great Britain.

German printed application, 1,046,502, January 1956. DONLEY I. STOCKING, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. A ROTARY PUMP COMPRISING FRONT AND REAR WALLS CONNECTED TOGETHER BY A CIRCUMFERENTIAL END WALL TO DEFINE A PUMPING CHAMBER, SAID END WALL HAVING A SINGLE CONTINUOUSLY SMOOTH INNER SURFACE, A PUMP IMPELLER SUPPORTED FOR ROTATION WITHIN SAID PUMPING CHAMBER, AN INLET OPENING THROUGH SAID FRONT WALL PERMITTING ACCESS OF FLUID TO BE PUMPED INTO SAID PUMPING CHAMBER, A DISCHARGE OPENING IN SAID END WALL PERMITTING FLUID TO EXHAUST FROM SAID PUMPING CHAMBER, AND A POCKET FORMED BY A CONTINUATION OF THE SINGLE CONTINUOUSLY SMOOTH INNER SURFACE OF SAID END WALL DEFINING AN ANNULAR CHAMBER IN SAID FRONT WALL TANGENT TO AND LOCATED ABOUT SAID INLET OPENING, SAID ANNULAR CHAMBER BEING OPEN TO SAID PUMPING CHAMBER WHEREBY A PORTION OF THE FLUID THEREIN ENTERS SAID ANNULAR CHAMBER AND IS REDIRECTED INTO SAID PUMPING CHAMBER TANGENTIALLY TO THE FLUID ENTERING SAID INLET OPENING. 